Whirling interlayer fields as a source of stable topological order in moir\'e CrI3

TL;DR

This study demonstrates the formation of stable topological spin textures in moiré CrI3 through interlayer vortex fields, revealing new mechanisms for magnetic order without relying on chiral interactions, with implications for spintronics.

Contribution

It uncovers the role of interlayer vortex and antivortex fields in stabilizing topological spin textures in moiré CrI3, highlighting the Dzyaloshinskii-Moriya interaction as a key spin-orbit coupling mechanism.

Findings

Interlayer vortex fields stabilize topological spin textures.

Dzyaloshinskii-Moriya interaction explains experimental observations.

Full spin dynamics including thermal fluctuations were modeled.

Abstract

The moir\'e engineering of two-dimensional magnets opens unprecedented opportunities to design novel magnetic states with promises for spintronic device applications. The possibility of stabilizing skyrmions in these materials without chiral spin-orbit couplings or dipolar interactions is yet to be explored. Here, we investigate the formation and control of ground state topological spin textures (TSTs) in moir\'e CrI3 using stochastic Landau-Lifshitz-Gilbert simulations. We unveil the emergence of interlayer vortex and antivortex Heisenberg exchange fields, stabilizing spontaneous and field-assisted ground state TSTs with various topologies. The developed study accounts for the full bilayer spin dynamics, thermal fluctuations, and intrinsic spin-orbit couplings. By examining the effect of the Kitaev interaction and the next nearest-neighbor Dzyaloshinskii-Moriya interaction, we propose the latter as the unique spin-orbit coupling mechanism compatible with experiments on monolayer and twisted CrI3. Our findings contribute to the current knowledge about moir\'e skyrmionics and uncover the nature of spin-orbit coupling in CrI3.